19... oops, 15 Ways to Start the 90s with a Bang!

Atari's Tengen division started out as a Nintendo licensee, then broke away from the official program to release games on its own, citing restraint of trade by Nintendo.  There was some serious corporate subterfuge involved, as Atari's lawyers obtained the NES lockout code under false pretenses, but Tengen managed to put out quite a few NES versions of Atari and Sega coin-op properties while the various suits and countersuits churned through the legal system.

Unfortunately, not all of the games in this two-page ad spread from 1990 actually made it to market:

Missing in action:  Xybots, Police Academy: The Video Game, License to Kill, and Hard Drivin' (which, believe it or not, actually exists in prototype form.)

What I've never understood is why Tengen was able to pay Sega to license conversion rights for Shinobi, Alien Syndrome, and Fantasy Zone, while resorting to deception to avoid paying Nintendo.  Nintendo's licensing program was famously restrictive -- but it also provided distribution and promotion support, and prevented flooding of the market with mediocre product (at least for a time).  Without those restrictions, third parties would have had a tough time making the scads of money most of them made in the NES era.

It's true that being out from under Nintendo's thumb avoided the five-titles-per-year restriction and allowed Tengen to produce quite a few games, most of which were better than the other unlicensed NES cartridges on the market.  But it really looks like a bad business decision in retrospect.

Although maybe not as bad as spending ad money to promote four games you're never going to release.